Five cases of severe neutropenia (neutrophil counts
We compare cases of severe neutropenia associated with tainted cocaine (NATC) identified in Alberta and BC between January 1, 2008 to March 31, 2009. Of the 42 NATC cases: 23(55%) were from Alberta; 19(45%) were from British Columbia; 57% of these cases reported crack cocaine use (93% of those who identified type of cocaine used); 7% reported using cocaine powder; and the main route of cocaine administration was from smoking (72%). Fifty percent of the NATC cases had multiple episodes of neutropenia associated with cocaine use. Cases typically presented with bacterial/fungal infections and fever. One Alberta NATC case produced anti-neutrophil antibodies, and four were positive for anti-neutrophil cytoplasmic antibody (ANCA). Analysis of two crack pipes and one drug sample obtained from NATC cases confirmed the presence of both cocaine and levamisole. A further 18 cases were identified through the retrospective review of laboratory and medical examiner data in Alberta
Making Crack With Levamisole Powder
Our findings support a link between neutropenia and levamisole tainted cocaine; particularly from smoking the crack form of cocaine. Some patients may be genetically predisposed to develop levamisole-related neutropenia. Awareness of the differential diagnosis will assist clinicians with case timely detection and appropriate management.
In 2008-2009, both Alberta and British Columbia public health officials investigated clusters of severe neutropenia associated with levamisole modified cocaine use; particularly in association with the smoking of crack cocaine. We present the findings from our investigations to increase awareness in clinicians and to improve the identification of cases.
In 2008, clinicians notified public health officials of five cases of severe neutropenia in Northern Alberta; cocaine and levamisole were detected in the urine of all five cases [14]. On November 21, 2008, Alberta Health Services disseminated a public health advisory to community partners and healthcare professionals [15]. The advisory highlighted the link between agranulocytosis and cocaine tainted with levamisole, the process for submitting urine samples for cocaine and levamisole toxicology, how to report cases and recommendations regarding case management. A broader provincial and national advisory shortly followed this communication. In response to Alberta's advisory and the identification of similar cases, the British Columbia Ministry of Health issued a provincial advisory on December 11, 2008 [16].
On November 18, 2008, the Clinical Toxicology Laboratories at the University of Alberta Hospital and Dyna LIFE DX in Edmonton began to append a clinical alert on all laboratory reports testing positive for cocaine. This alert highlighted the relationship between neutropenia and cocaine tainted with levamisole. Identification of levamisole in urine was limited to a few facilities in Alberta and none in British Columbia. The University of Alberta Hospital Toxicology Laboratory in Edmonton agreed to conduct levamisole testing on behalf of British Columbia. A literature review was performed to inform the investigation.
Patients presenting with severe neutropenia (defined as neutrophil counts less than 0.5 per 109 cells/L), and recent cocaine use in Alberta or British Columbia between January 1, 2006 and March 31, 2009 were identified as cases of Neutropenia Associated with Tainted Cocaine ("NATC"); specifically, levamisole tainted cocaine. Cases were categorized as confirmed, probable, or suspect NATC cases (see Appendix 1). Only confirmed and probable NATC cases are presented in this paper.
Alberta performed retrospective chart review using laboratory and medical examiner data. Retrospective laboratory data was obtained from the Edmonton, Calgary, Chinook, East Central and Peace areas of Alberta between January 1, 2006 and March 31, 2009. NATC cases identified through the laboratory and medical examiner data review processes involved searching for potential cases with concurrent laboratory results indicative of severe neutropenia and positive cocaine, cocaine metabolites and/or levamisole screens. Where possible these NATC cases were further cross-referenced with electronic medical records, to determine any NATC exclusion factors and documented risk factors.
Health Canada Drug Analysis Service provided testing for cocaine and levamisole markers in suspected cocaine samples and paraphernalia. Toxicology Laboratories in Edmonton and Calgary tested urine for cocaine, its metabolites, and levamisole; the University of Alberta Hospital Toxicology Laboratory also tested drug paraphernalia related to current patients. Clinicians were requested to collect urine specimens for toxicology testing from identified neutropenic patients if within 48 hours of cocaine consumption. Typically, neutrophil counts were performed when patients sought medical care.
Forty-two cases of NATC were identified in Alberta and British Columbia from January 1, 2008 to March 31, 2009. In this time period, 16 confirmed, and 26 probable, NATC cases were identified. Eighteen (43%) NATC cases had recurrent episodes of neutropenia associated with cocaine use (range: 2 to 8 episodes). The dates of NATC case identification are shown in Figure 1. Characteristics of these 42 NATC cases are presented in Table 1; 64% of cases were female. Of the NATC cases where cocaine details were obtained, most (93%) used crack cocaine; two probable cases reported only using cocaine powder. The main route of cocaine consumption was smoking (72% where route was known).
Reported history of cocaine use varied from occasional use to chronic use and binging. Ten of the 16 confirmed NATC cases (63%) used crack cocaine within two days of seeking medical care, some within hours of seeing a physician. Five NATC cases indicated heavy crack cocaine usage (1 to 3 grams per day) just prior to admission.
Some differences in NATC case characteristics between the Alberta and British Columbia cohorts were noted. British Columbia identified 13 (68%) NATC cases of aboriginal heritage, four cases (17%) in Alberta were identified as Aboriginal. In Alberta, one death was associated with the consumption of levamisole tainted crack cocaine. One NATC case in Alberta was tested for and produced anti-neutrophil antibodies, both IgG and IgM subtypes, as detected by flow cytometry and HLA Class I antigens. For another five NATC cases, anti-neutrophil cytoplasmic antibody (ANCA) tests were conducted; four NATC cases were positive (two for pANCA; two for cANCA).
The contents of two used crack pipes obtained from NATC cases verified the presence of cocaine and levamisole. One sample of cocaine was tested for levamisole and found to be positive; quantifying the percentage of levamisole in the sample was not possible in Canada at that time.
We identified a total of 60 NATC cases and 108 episodes of neutropenia associated with levamisole-tainted cocaine, in Alberta and British Columbia since June, 2006. Most cases were related to smoking crack, and some cases reported heavy use prior to seeking medical care; though we were unable to confirm a dose response.
Some patients may be genetically predisposed to develop levamisole-related neutropenia. Prior studies found people with levamisole-related neutropenia were more likely to have HLA-B27, an HLA class I antigen [21]. As routine HLA-B27 testing is difficult, the utility of this risk factor is unknown.
Levamisole is known to have immunostimulating effects with the production of auto-antibodies [22]. Anti-neutrophil antibodies found in patients who develop neutropenia after levamisole use have been postulated as a potential cause for the neutropenia [23]. ANCA have also been implicated in drug-induced neutropenia [24]. In our investigation we found one case positive for anti-neutrophil antibodies and four positive for ANCA, which support the speculation that these auto-antibodies may cause levamisole-related neutropenia.
Despite public health notification and media interest in both provinces the true burden of NATC is likely underestimated by voluntary reporting of NATC cases by clinicians. As levamisole has a short half-life (approximately 5 to 6 hours) and little (2 to 5%) is excreted unchanged in urine, specimens should be collected within 48 hours of exposure [25, 26]. Thus delayed identification of NATC cases may have led to missed urine levamisole testing and case confirmation. The misclassification of NATC cases based on other competing health conditions may have occurred. Finally, NATC case findings were limited by the lack of accessibility to retrospective laboratory data and the availability of levamisole testing in British Columbia.
Clinicians should be aware that severe neutropenia may be caused by levamisole in cocaine. If fever or infection is present, empiric intravenous broad spectrum antibiotics and supportive care is recommended and treatment with granulocyte-colony stimulating factor (G-CSF or filgastrim) should be considered [14]. The majority of patients respond within days of treatment [14], but neutropenia may recur on subsequent exposure. Following the public health advisories, fewer patients underwent invasive procedures such as bone marrow biopsies.
We also recommend that clinicians inquire about patients' recent cocaine use (see Appendix 2) and request levamisole testing if urine is obtained within 48 hours of last cocaine use. The diagnosis should still be considered when patients present with other coexisting health conditions (e.g. HIV).
In conclusion, neutropenia associated with levamisole-tainted cocaine presents a significant, emerging public health problem in Canada. For clinicians, the awareness of the differential diagnosis for neutropenia can ensure timely diagnosis and appropriate management of cases. 2ff7e9595c
Comments